1. Field of the Invention
This invention generally relates to laparoscopic scissors and, more particular, to laparoscopic scissors having multiple cutting angles and multiple thicknesses.
2. Discussion of Related Art
During surgery, surgeons will typically need to cut into a multitude of objects such as tissues, suture and metal staples. A goal in the design of scissors and, in particular, in the design of scissors' blades is to optimize its effectiveness in cutting through different objects. For cutting through soft tissues, a large angle ground into the blade is most effective. That is, when sharp edges shear against each other, any tissue which comes between the blades of the scissors will get cut. The large angle on each blade is effective when cutting soft material because the blades can stay thin and razor sharp throughout the cut. A thin and sharp edge is optimal for soft materials because there is less resistance throughout the cut.
In contrast, when cutting through something hard such as a metal staple, the fine edge of a typical scissors' blade may not be as effective as when cutting soft tissue. A very fine and sharp edge may deform when required to cut a hard object. That is, a blade having a very large angle ground into it will deform if used to cut hard objects. To prevent the blades from deforming, the blades have to be designed to be thicker at and behind the point of cutting so that the blade edges do not deform. Having a small angle on the cutting edge of a scissor blade like this would help when cutting through hard materials such as staples or hard objects. Accordingly, because tissue and staples are typically cut with the same instrument, there is a need in the art for a laparoscopic scissors having both a large angle cutting edge and a small angle cutting edge on the same device.